FR2919058A1 - METHOD AND INSTALLATION FOR TESTING CATALYSTS - Google Patents

Abstract

The invention relates to a method for testing the performance and / or the evolution over time of at least one catalyst CAT for fixed bed reactor comprising at least the following steps: - is connected to a point A of an installation industrial chemical using a reaction charge suitable for the CAT catalyst test, a CT test device, comprising at least one hollow metal cartridge MC containing in particular the CAT catalyst, is taken at point A a fluid stream consisting of a fraction less than or equal to 1 % of the preheated reagents circulating in the industrial chemical plant, which is circulated in the cartridge MC through the catalyst CAT, at a reaction temperature for a period T, - is taken for chemical analysis at least a fraction of the effluent from the cartridge MC, the test device CT of the industrial chemical plant is optionally isolated without stopping the operation thereof and the at least one fraction of the CAT catalyst is taken for physical and / or chemical analysis. The invention also relates to an industrial chemical plant comprising the device for bypass CT testing.

Description

Field of the invention

  The invention relates to the field of the test of the efficiency and the behavior over time of fixed bed industrial catalysts, in particular supported catalysts, for example beads or extrusions, most often constituted by one or more catalytically active elements arranged on a porous support, for example alumina, silica-alumina, zirconia, etc.

  It is not related to a particular chemical reaction or a particular catalyst. Examination of the Prior Art: The efficiency (or performances) of a fixed bed catalyst depends on the operating conditions (in particular temperature, pressure and space velocity VVH) and can be measured according to several criteria: the conversion obtained for a charge given under given operating conditions, the selectivity of this conversion, in particular vis-à-vis one or more sought products, and more generally the spectrum of products obtained.

  The efficiency and the performance over time of a catalyst are generally not constant. Apart from possibly during an initial phase of initiation and start-up where the catalyst can sometimes have an increasing activity, there is generally a certain deactivation of the catalyst over time, which can be manifested by a loss of activity and / or selectivity, continuous or substantially asymptotic or according to other modes of catalytic behavior. This evolution over time of a catalyst can result from multiple factors that can possibly be combined. Coking, in particular the deposition of other impurities, for example non-limiting metals, which may clog the pores of the catalyst, reduce its surface area and / or cause diffusional limitations can be cited in particular. A catalyst can also lose active sites by different mechanisms, for example catalyst poisons, reversible or not, and / or see its structure evolve, for example by falling porosity and / or the surface of the support.

  The performance of a catalyst also depends on the nature of the charge, the presence of impurities and / or inhibiting compounds.

  Catalyst manufacturers therefore have to carry out catalyst tests at the laboratory, at different dimensional scales, for example on micropilots, or on larger pilot sizes. It is also necessary to carry out tests of different charges, with different operating conditions, comparative tests of several different catalysts, long-term tests to assess the evolution over time of the catalyst and its performance, etc.

  All these tests are particularly expensive in terms of investment, energy consumption and loads etc ... They are carried out on test installations, or pilot installations, some carrying out the test of a single catalyst, and others the test of several catalysts generally operating in parallel.

  The effluent analysis of the pilot plant is typically carried out, and often the analysis of the catalyst is carried out after a desired period of operation.

  These chemical analyzes constitute a vast field well known to those skilled in the art. A large number of chemical analysis techniques are commonly used in laboratories, such as GC or liquid LC analysis, IR (infrared) spectroscopy, MS (mass spectroscopy), NMR (magnetic resonance) nuclear), "X-ray fluorescence", "UV fluorescence", ICP ("inductively coupled plasma" which means inductively coupled plasma), AA (atomic absorption), ATD-ATG (thermodifferential / thermo-gravimetric analysis), observation using an electron microscope, measurement of the BET surface of the catalyst, etc. These techniques are part of the general knowledge of those skilled in the art.

  In the state of the art, however, there are no processes and devices which make it possible to significantly reduce the costs resulting from catalyst tests, in particular for long-term tests. Brief presentation of the invention:

  An object of the present invention is a method of performance testing and / or

  The evolution over time of at least one catalyst CAT implementation much less expensive than that of a conventional pilot plant catalyst test in the laboratory.

  In particular, the process according to the invention makes it possible to significantly limit the necessary thermal means and the consumption of reagents.

  Another object of the invention is to allow a comparative test of catalyst under conditions closer to those of industrial operation.

  Another object of a preferred variant of the invention is to be able to perform tests of much longer duration more economically, in particular with respect to the consumption of reagents.

  For this purpose, the invention proposes to graft a catalyst test device CT on an industrial plant in operation, and to take a small fraction of the flow of reagents circulating in the industrial unit to perform the test of at least one bed a CAT catalyst. The device CT may advantageously comprise at least one and preferably at least two hollow metallic cartridges MC in parallel making it possible to test two different catalysts under the same operating conditions or the same catalyst under different operating conditions.

  This implementation according to the invention of a test installation connected to an existing industrial installation saves the whole logistic part for the supply of reactive charge which is taken typically under pressure and already at the reaction temperature. The test device can then be equipped with limited thermal means, for example simple means for maintaining temperature, without providing the power required for heating to the reaction temperature.

  According to a preferred variant, the CT device is installed as a bypass on the industrial installation, which makes it possible to reinject the CT effluents into the industrial installation. As a result, there is no loss of reagents (charge) and the test can be performed at zero charge consumption.

  The invention also relates to an industrial chemical plant comprising a catalyst test device connected to this installation. It also covers several variants of such an installation, in particular when CT comprises at least two cartridges MC in parallel and / or when CT is installed in bypass. Detailed presentation of the invention: The invention proposes, in a more Specifically, a method of performance testing and / or the evolution over time of at least one CAT catalyst for fixed bed reactor comprising at least the following steps: - is connected to a point A of an industrial chemical plant using a reaction charge suitable for the CAT catalyst test, a CT test device, comprising at least one hollow metal cartridge MC containing in particular the CAT catalyst, is taken at point A a fluid stream consisting of a fraction less than or equal to 1% of the preheated reagents circulating in the industrial chemical plant, which are circulated in the cartridge MC through the catalyst CAT, at a temperature reaction During a period of time T, at least a fraction of the effluent from the cartridge MC is removed for chemical analysis. The test device CT of the industrial chemical plant is optionally isolated without stopping the operation thereof. at least one fraction of the CAT catalyst is taken for physical and / or chemical analysis. This makes it possible to benefit from all the logistics of supplying the preheated reaction charge for the test of the performance and the evolution of the catalyst.

  According to a first characteristic variant of the process according to the invention, the fluid stream is circulated in a device CT comprising at least 2 cartridges in parallel MC1 and MC2 containing different catalysts, respectively CATI and CAT2, the same reaction conditions are maintained for the cartridges MC1 and MC2 and samples are taken of the separated effluents of MC1 and MC2 which is carried out a comparative chemical analysis. This makes it possible to be able to test two different catalysts under strictly identical conditions, in order to perform a reliable comparative test. According to a second characteristic variant of the process according to the invention, the fluid stream is circulated in a device CT comprising at least two cartridges in parallel MCa and MCb containing the same CAT catalyst, different reaction conditions are maintained for the cartridges MCa and MCb and separate effluent samples are taken from MCa and MCb which is performed a comparative chemical analysis. This makes it possible to test the influence of the operating conditions on the performances of the catalyst (conversion, selectivity, etc.).

  The process according to the invention also makes it possible to analyze the catalyst (s) tested: The CT test device is isolated from the industrial chemical installation without stopping the operation thereof, at least one fraction of the catalyst CAT is removed, or where appropriate, at least a fraction of CATI and at least a fraction of CAT2, which is analyzed in the laboratory by means external to the CT device.

  An MC cartridge may contain from 2 to 5 physically separated beds of CATi elemental catalysts, identical or different, optionally preceded by one or more guard beds, for eliminating certain impurities. This makes it possible to analyze the evolution of the same catalyst at different degrees of conversion of the feedstock: the CT test device is isolated from the industrial chemical installation without stopping the operation of the latter, and a at least a fraction of at least several, and typically all of the CATi elemental catalysts that are analyzed in the laboratory. The test device CT may in particular comprise a moisture adsorbent disposed upstream of the catalyst CAT, disposed in the cartridge MC, or optionally MC1 and / or MC2 and / or MCa and / or MCb, or in at least one specific removable cartridge WR arranged upstream of MC. It may also comprise several different catalysts in series. The test device CT generally comprises heating means and the fluid current and / or the cartridge MC, or, if appropriate, MC1 and / or MC2 and / or MCa and / or MCb are heated in order to maintain and / or obtain an adequate reaction temperature. These heating means are in particular to compensate for heat losses. In some cases, an additional heating power is used to test the possibility of chemical reactions with heating integrated in the reactor, or more severe operating conditions.

  According to a preferred characteristic variant of the process according to the invention, a downstream part of the device CT is connected to a point B of the industrial chemical plant for the reinjection into this installation of the CT effluents, CT being in derivation between the points A and B of the industrial chemical plant. This variant has great advantages: Indeed, the reaction charge through CT is not lost, but returned to the industrial plant, and therefore valued, which is not the case for laboratory catalyst tests for which the Recovery management of effluent separation typically excludes any economic valuation. The invention therefore also makes it possible to carry out tests of long duration, greater than 3 months, or 6 months or even very long duration greater than 1 year, or 2 years or even 3 years, on actual load, without particular additional cost.

  It is thus possible to test the long-term evolution of the catalysts and their performances.

  The invention also relates to a CIF industrial chemical installation comprising at least one fixed-bed catalytic reactor R comprising a test CT device installed as a bypass between two points A and B of this installation, A being located upstream or at the reactor R, CT comprising at least one hollow metal cartridge MC containing at least one CAT catalyst, and at least one sample taken on the effluents of the cartridge MC and / or on-line analysis means of these effluents, the ratio of catalytic volume of R on the catalytic volume CAT being at least 100, often at least 1000, and generally at least 10000. Generally, the volume of catalyst tested is very low, for example between 1 cm3 and 5 liters, especially between 10 cm3 and 2 liters, and most often between 100 cm3 and 1 liter, which is typically negligible vis-à-vis the catalytic volume of an industrial chemical reactor.

  The CT device of the CIF plant may comprise at least one catalyst bed CAT different from the reactor R catalysts or catalysts, for example to test another catalyst, for example an optional replacement catalyst. It may also comprise at least one MC cartridge containing at least one CAT catalyst bed identical to one or to one of the catalysts of the reactor R, in order to readjust the performances of the catalyst in the test cartridge MC with those of the industrial reactor.

  The CT device of the CIF installation may also comprise at least 2 parallel cartridges MC1 and MC2 containing different catalysts, respectively CATI and CAT2, in particular to perform reliable comparative tests under the same conditions and operating simultaneously on the same load .

  The CT device of the CIF installation may also comprise at least two parallel cartridges MCa and MCb respectively containing at least one bed of the same CAT catalyst and separate means for heating the two cartridges MCa and MCb.

  The CT device of the CIF installation generally comprises thermal heating means and means for controlling the outlet temperature of at least one metal cartridge MC, or optionally MC1 or MC2 or MCa or MCb, in order to be able to maintain in temperature and / or heat the fluid stream of the reaction charge. It may also comprise thermal heating means and means for controlling the outlet temperature (s) of at least two metallic cartridges in parallel: MC1 and MC2 or, if appropriate, MCa and MCb. This makes it possible to test different temperatures in the two cartridges in parallel.

  The CT device of the CIF installation may comprise at least one metal cartridge MC, or optionally MC1 or MC2 or MCa or MCb in which are arranged from 2 to 5 physically separate beds in series of elementary catalysts CATI, identical or different. Thus, one can follow the evolution in time: physical evolution (surface, porosity, structure etc ...) and / or chemical (number of active sites etc ...) of the catalyst at different successive stages of the chemical reaction. These different serial beds of elementary catalysts CATI can each be arranged in a CELL metal retention structure allowing their separate extraction from the MC cartridge or cartridges. Each of the metal retention structures CELL may in particular comprise in the lower part a permeable support of the corresponding CAPTi mass, a ferrule section of diameter less than the inside diameter of the corresponding cartridge MC, and a means of limiting the bypass flow around this ferrule section. The various elemental catalysts CATI can also be arranged between inert balls, for example carborundum, or between ceramic fiber layers, for example quarz wool, or separated by any other suitable means.

  DESCRIPTION OF THE FIGURES FIG. 1 schematically represents a CT device that can be used for carrying out the method according to the invention. FIG. 2 diagrammatically represents a reactor of a CIF industrial chemical plant equipped with two CT and CT * bypass devices used for the implementation of a variant of the process according to the invention. FIG. 3 schematically represents a preferred cartridge MC of a CT device that can be used for carrying out the method according to the invention. Referring now to Figure 1: The device comprises a line 1 for supplying a fluid stream taken at a point A on a reaction charge of an industrial chemical reactor R. The feed line is subdivided into two branches 2, 5, and 6, 9 each comprising a removable hollow metal cartridge, respectively MC1 and MC2, isolable between two valves, respectively 3, 4 and 7, 8. These cartridges are filled with several successive layers of catalyst. For example, the cartridge 4a contains 3 successive layers of a first catalyst CATI identical to the industrial catalyst of the reactor R, and the cartridge 4b contains 3 successive layers of a second catalyst CAT2 which one seeks to evaluate as a catalyst of replacement. Each of these two cartridges may optionally comprise upstream one or more guard mass (s) intended (s) to protect the catalysts CATI and CATb against poisons of these catalysts (water, mercury, H2S etc ...). The reaction fluid stream withdrawn therefore reacts on the two catalysts CATI and CAT2 in parallel. Two heating resistors 21 and 22 controlled by temperature control means TC1 and TC2 make it possible to separately heat the cartridges MC1 and MC2 to maintain the temperature and / or independently obtain the desired output temperatures of the two effluents of these catalytic cartridges. Two sample points 23 and 24 are used to take samples of the MC1 and MC2 effluents for comparative chemical analysis.

  Downstream, the effluents of MC1 and MC2 are combined and circulate in a line 10 whose flow rate is controlled by means FC flow control. The effluents are then discharged via line 11 to the point B which is for example the connection point downstream of the industrial reactor R. It is also possible to control separately the flow rates in the cartridges MC1 and MC2, for example by means other than shown as manual or regulating valves, to ensure identical flow rates. This installation operates as it has already been explained above, allowing to test different catalysts under the same conditions. If CATI is identical to CAT2, one can also test the influence of different operating conditions such as the space velocity and / or the temperature. Finally, it is clear that one can take samples of the catalysts tested for physical and / or chemical analysis, without stopping the industrial installation CIF and the reactor R. Referring now to FIG. CT and CT * are installed in bypass at several points around and at the level of a chemical reactor 40 comprising two catalytic beds 41 and 42. The reactor 40 is supplied with a fluid current (reagents) from a line 30, and the effluent from the reactor is discharged via line 35. The first CT catalyst test device, the most upstream, is connected to a point A upstream of the reactor and a very small fraction of the fluid stream (for example less than 1 / 1000 or 1/10000 of the overall fluid flowing in the industrial unit, for example between 1/1000 and 1/1000000 of the overall fluid) is taken, feeds bypass CT via the line 31, crosses CT, and the effluent of CT is reinjected via the l 32 in the reactor at a point B located between the two catalytic beds 41 and 42. The second CT * catalyst test device, the most downstream, is connected to an intermediate point A * of the second catalytic bed 42, and a very small fraction of the reaction fluid stream (for example less than 1/1000 or 1/10000 of the overall fluid) is withdrawn, feeds bypass CT * via line 33, crosses CT *, and the effluent of CT * is reinjected via the line 34 at a point B * situated on the outlet line 35 of the reactor 40. In this configuration, it is possible both to test catalysts for replacing the industrial catalyst of the first bed catalytic bed 41, by the catalyst or catalysts (s) tested in CT, and those that can replace the industrial catalyst of the end of the second catalytic bed 42, these being tested in CT *. More generally, it is possible to use a plurality of CT devices in derivation. Referring now to Figure 3 showing a capture cartridge MC of one of the preferred types according to the invention. This cartridge comprises an elongate cylinder 51 containing several successive series 50 catalysts (and possibly upstream protection capture masses), physically separated and stackable one on the other. to form the global capturing mass. Each catalyst is arranged in a basket comprising a grid or a perforated sheet in the lower part, of opening size small enough so that the catalyst grains do not pass through. The baskets are typically self-supporting which allows their overall stacking. The bottom edge of a basket rests on the top edge of the basket immediately below. The upper edge of a basket is also advantageously used for its gripping and extraction of the cartridge MC.

  The baskets can be machined to leave only minimal clearance with the metal ferrule of the MC cartridge. It is also possible to arrange a seal (not shown in FIG. 3), for example a braid around each basket, to prevent the catalyst from being bypassed by part of the reaction fluid. The cartridge also includes two removable flat bottoms 52 for extracting the baskets. The invention is not limited to the means explicitly described, and may include any characteristic already known in the fields of catalyst testing and the analysis of chemical compounds.

Claims (18)

claims   1. A method for testing the performance and / or the evolution over time of at least one catalyst CAT for fixed bed reactor comprising at least the following steps: is connected to a point A of an industrial chemical plant using a a test device CT, comprising at least one hollow metal cartridge MC containing in particular CAT catalyst, is taken at point A a fluid stream consisting of a fraction less than or equal to 1% of the preheated reagents circulating in the industrial chemical plant, which is circulated in the cartridge MC through the catalyst CAT, at a reaction temperature for a period T, - is removed for chemical analysis at least a fraction of the effluent of the cartridge MC, the test device CT of the industrial chemical installation is optionally isolated without stopping the operation of the latter and a sample is taken at least CAT catalyst for physical and / or chemical analysis.   2. Method according to claim 1, wherein said fluid stream is circulated in a device CT comprising at least 2 parallel cartridges MC1 and MC2 containing different catalysts, respectively CATI and CAT2, the same reaction conditions are maintained for the cartridges MC1. and MC2 and separate effluent samples are taken from MC1 and MC2 which is performed a comparative chemical analysis.   3. Method according to one of the preceding claims, wherein said fluid stream is circulated in a CT device comprising at least two cartridges in parallel MCa and MCb containing the same CAT catalyst, different reaction conditions are maintained for the cartridges MCa and MCb and samples are taken of effluents separated from MCa and MCb which is carried out a comparative chemical analysis.   4. Method according to one of the preceding claims, wherein the CT test device is isolated from the industrial chemical plant without stopping the operation thereof, taking at least a fraction of the catalyst CAT, or optionally a at least a fraction of CATI and at least a fraction of CAT2, which is analyzed in the laboratory by means external to the CT device.   5. Method according to one of the preceding claims, wherein an MC cartridge contains 2 to 5 physically separate beds in series of elementary catalysts CATI, identical or different, optionally preceded by one or more beds of mass (s) guard, the CT test device is isolated from the industrial chemical installation without stopping the operation thereof, and at least a fraction of at least several of the CATI elemental catalysts that are analyzed in the laboratory are removed.   6. Method according to one of the preceding claims, wherein a downstream portion of the CT device is connected to a point B of the industrial chemical plant for the reinjection into this installation of CT effluents, CT being in branch between points A and B of the industrial chemical plant.   7. Method according to one of the preceding claims, wherein said fluid stream is circulated in a CT device comprising a moisture adsorbent disposed upstream of the catalyst CAT, arranged in the cartridge MC, or optionally MC1 and / or MC2 and / or MCa and / or MCb in at least one specific demountable cartridge WR disposed upstream of MC.   8. Method according to one of the preceding claims, wherein said fluid stream is circulated in a device CT comprising heating means and said fluid stream is heated and / or the cartridge MC, or the caséchéant MC1 and / or MC2 and / or MCa and / or MCb to maintain and / or obtain a reaction temperature.   9. CIF industrial chemical installation comprising at least one catalytic reactor R in a fixed bed and comprising a test CT device installed as a bypass between two points A and B of this installation, A being situated upstream or at the level of the reactor R, CT comprising at least one hollow metal cartridge MC containing at least one CAT catalyst, and at least one sample taken on the effluents of the cartridge MC and / or on-line analysis means for these effluents, the ratio of the catalytic volume of R on the catalytic volume CAT being at least 100.   10. Installation according to claim 8 wherein the device CT comprises at least one cartridge MC containing at least one CAT catalyst bed different from the catalyst (s) contained in the reactor R.   11. Installation according to claim 8 wherein the device CT comprises at least one hollow metal cartridge MC containing at least one CAT catalyst bed identical to the catalyst, or to one of the catalysts contained in the reactor R.   12. Installation according to one of claims 8 to 11 wherein the CT device comprises at least two cartridges in parallel MC1 and MC2 containing different catalysts, respectively CATI and CAT2.   13. Installation according to one of claims 8 to 11 wherein the device CT comprises at least two cartridges in parallel MCa and MCb respectively containing at least one bed of the same catalyst CAT and separate means for heating the two cartridges MCa and MCb.   14. Installation according to one of claims 8 to 13 wherein the device CT comprises thermal heating means and control means 30de the exit temperature of at least one metal cartridge MC, or where appropriate MC1 or MC2 or MCa or MCb.   15. Installation according to one of claims 12 and 13 wherein the CT device comprises thermal heating means and means for controlling the temperature (s) output (s) of at least two metal cartridges in parallel: MC1 and MC2 or where appropriate MCa and MCb.   16. Installation according to one of claims 8 to 15 wherein the device CT comprises at least one metal cartridge MC, or optionally MC1 or MC2 or MCa or MCb in which are arranged from 2 to 5 beds physically separated in series from elementary catalysts CATI, identical or different.   17. Installation according to claim 13 wherein said serial beds of elementary catalysts CATI are each arranged in a CELL metal retention structure allowing their separate extraction of the MC cartridge or cartridges.   18. Apparatus according to claim 13, wherein each of the CELL metal retention structures comprises in the lower part a permeable support of the corresponding CAPTi mass, a ferrule section of diameter less than the inside diameter of the corresponding cartridge MC, and a means of limit the bypass flow around this ferrule section.